What If Life Did Not Originate on Earth? | The New Yorker


12 bookmarks. First posted by flobosg 8 days ago.


Isaac Chotiner speaks with Gary Ruvkun, a molecular biologist and professor of genetics at Harvard, who wants to search for DNA on Mars.
prismo 
4 days ago by thx1138
I think viewing life as having started here is a little bit presumptuous. It seems we’re very, very, very special and it all happened here. I find the idea aesthetically appealing that life as we know it is universal across the Milky Way. It just seems like, once it evolves, it spreads. And one way to argue this is running the clock forward instead of running it in reverse. If we’re really talking about colonizing Mars, step one is to send bacteria to Mars to generate an atmosphere. So if you run the clock forward a million years, presumably, we will be sending bacteria to planets a million light years from us.

They’d say that’s just stupid. [Laughs.] Because they’re saying, “Well, it had to start somewhere, and so why would you not think it started here? Why are you positing that we caught life instead of evolved it?” Because there’s clearly evidence for how life evolved in our genomes. It’s what’s called the RNA World, which was kind of the earliest form of life, and is still present in our genomes. We can see it there, and so you can discern early steps in evolution just by looking in modern genomes. In orthodoxy and all the textbooks, the RNA World—that’s kind of the precursor to the DNA world—was here on Earth four billion years ago. And I would propose, no, it was probably ten billion years ago, somewhere on the other side of the Milky Way, and it’s been spreading all across the Milky Way.
5 days ago by spectrevision
What If Life Did Not Originate on Earth? via Instapaper https://ift.tt/32ebFAt
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6 days ago by Samcochrane
For almost seven years, NASA’s Curiosity rover has been exploring the terrain of Mars. Two weeks ago, it made a stunning discovery: relatively large concentrations of methane gas. July 08, 2019 at 12:16PM
6 days ago by colin.eide
Isaac Chotiner:
<p>For almost seven years, Nasa's Curiosity rover has been exploring the terrain of Mars. Two weeks ago, it made a stunning discovery: relatively large concentrations of methane gas. The rover also found methane in 2013, but the readings recorded this month—approximately twenty-one parts per billion—were about three times as concentrated. The reason this news registered among scientists is that methane is often a sign of life; although the gas can be produced by various chemical reactions, most of it comes from animate beings. Does this mean that we are on the verge of discovering life on Mars, and, if so, what kind of life is it likely to be?

To discuss these questions, I spoke by phone with Gary Ruvkun, a molecular biologist and professor of genetics at Harvard Medical School. Ruvkun has what he admits are somewhat unusual opinions about life’s origins, and about the possibility of finding life elsewhere. In short, he questions the common assumption that our form of DNA-based life began on Earth. What began as an interview about the methane discovery turned into a discussion about why he wants to send something called a DNA sequencer to Mars. (After our conversation, NASA announced that the methane concentrations had descended back to their usual levels, further confounding scientists.) During our conversation, which has been edited for length and clarity, we also discussed the ways in which scientific debates about the origins of life intersect with religious ones, the reasons he might be dead wrong, and what it feels like to hold a minority opinion in the scientific community.</p>


Chotiner's interviews are always worth reading: he has an exceptional ability to ask the right questions, and knowledge of the topic that helps to get deeper into it than the standard Q+A.
space  evolution  history  earth  dna 
7 days ago by charlesarthur
RT : Some compelling ideas around panspermia:
from twitter
7 days ago by mshook
The Curiosity rover recently discovered methane on Mars, which could be a sign of life. The biologist and genetics professor Gary Ruvkun wants to search for DNA…
from instapaper
7 days ago by alexdunae
Bacteria from 3B years ago was far too complex to have started from nothing when the earth formed 4.5B years ago
space  life  earth  history  science 
7 days ago by ianchanning
The Curiosity rover recently discovered methane on Mars, which could be a sign of life. The biologist and genetics professor Gary Ruvkun wants to search for DNA…
from instapaper
8 days ago by flobosg